diff --git a/lesscpy/lib/dom.py b/lesscpy/lib/dom.py
index 2a1f96c..3ad30e6 100644
--- a/lesscpy/lib/dom.py
+++ b/lesscpy/lib/dom.py
@@ -101,6 +101,7 @@ html4 = [
     'print',
     'screen',
     'all',
+    'only',
     'projection',
     'from',
     'to'